The present invention relates to a damper for a cassette holder and, more particularly, to a damper for a cassette holder whose structure is improved to be opened and closed by a constant opening force regardless of environmental influences such as temperature.
Generally, a rotary cassette loading device is adopted in a camcoder. FIG. 1 schematically shows this cassette loading device. Reference numeral 4 represents a chassis installed at both sides of a deck (not shown) on which a reel table for loading a reel of cassette (not shown) thereon are mounted. A holder 1 for receiving a cassette is rotatably connected to one end of chassis 4 by a hinge 7. Since holder 1 and chassis 4 are connected by a spring 13 as shown in FIG. 2, holder 1 is opened by the spring force as shown in FIG. 1. Reference numeral 1' denotes a protrusion extending from a lever 2 of holder 1, and reference numeral 4' denotes a protrusion extending from chassis 4.
Thus, locking means (not shown) should be comprised for loading a cassette received in the holder 1 onto the deck. When the locking means is released, the holder 1 is opened by the force of the spring 13. Here, since the spring force is strong, the holder 1 tends to slam open noisily and parts such as the hinge 7 are damaged.
To solve the above problems, a damper is adopted in a cassette loading device.
As shown in FIGS. 1-3, the damper comprises a casing 9 filled with a damping substance 10 such as oil, a rotary plate 12 rotating in a submerged state in the damping substance 10, and a cover 11 which is connected to casing 9.
Rotary plate 12 has a shaft 12' whose one end is supported by casing 9 and whose other end passes through cover 11. On the other hand, a hook 9' is formed on the casing 9 and a locking slot 2', which is connected with the hook 9', is formed on holder 1. Shaft 12' protrudes to the other side of holder 1 via a penetration opening 2" of holder 1.
A gear 8, which is connected with the shaft 12', is mounted on the other side of the holder 1. The gear 8 is installed to be meshed with a sector gear 6 formed in the chassis 4. Reference numeral 14 denotes a ring member for preventing the leakage of the damping substance 10.
The damper reduces the spring force using the damping substance 10 when the locking means is released and simultaneously the holder 1 is opened by the force of the spring 13. That is, when the holder 1 is opened, the gear 8 rotates counterclockwise while being meshed with the sector gear 6 and simultaneously the rotary plate 12 rotates counterclockwise while submerged in the damping substance 10. Here, the rotary speed of the gear 8 and the rotary plate 12 is decreased due to the rotary resistance caused by the viscosity of the damping substance 10 so that the holder 1 is opened more slowly.
However, the damper as described above has the following problems.
First, product reliability is reduced since the opening force of the holder varies due to inconsistent quantities of the damping substance 10 filling the casing 9.
Second, the opening force of the holder is different according to the ambient temperature, since the viscosity of the damping substance varies according to the temperature.
Third, the cost is high due to the many parts to be assembled.